1. Field of the Invention
The invention is directed to a trench shoring system for use in trenches such as those for burying pipes underground, and particularly, a trench shoring system which utilizes double sliding panels to prevent collapse of the walls of the trench.
2. Description of Related Art
Currently, there exists a trench shoring system using panels to prevent soil collapse. In this system, two or more struts are affixed to slide rails. Two sets of this ladder-like structure are assembled. First, one set is driven vertically into the trench, then one end of each of two panels are fitted onto the slide rails, and then the other ladder-like structure is fitted onto the other end of the two panels. As the section of the trench inside this box-like structure is dug, the panels and the slide rails are driven in turns, and this step is repeated continuously until the panels reach a specified depth.
Concerning this system, panels are used in two levels, upper and lower. The lower panel is called the edged panel and the upper panel is called the extension panel. If the depth of the trench exceeds 5 m, double rails, which are slide rails with double grooves for inserting panels into, are also used.
With this conventional trench shoring system, as illustrated in FIGS. 5-9, after a preliminary ditch is dug, the front slide rails are driven in at the front end of the trench. Then two edged panels, which are panels with a pointed edge along the bottom, are fitted at one end into the front slide rails and driven in. After that, at the other end of the trench, back slide rails are fitted onto the other end of the edged panels and driven into the trench. This results, at the end, in a safe, box-like trench shoring structure. However, during the assembly of this structure, when the edged panels are being fitted into the front slide rails and driven in, or when the back slide rails are being driven into the free end of the edged panels, the work may be dangerous and difficult.
Also, similarly, after the back slide rails are driven in, when the front slide rails are being driven deeper into the trench floor, or when the extension panels are being fitted into the slide rails after the edged panels have been driven deeper into the trench floor, the work may be difficult.
Additionally, while digging to the desired depth, when driving in the inner panels and slide rails by pushing from on top with the bucket of an excavator, especially when the slide rails are double rails, there is the possibility of the problem of the outer panels, the top of which should be at ground level (GL) to stabilize the natural ground walls of trenches, falling or sinking further into the ground due to the vibration caused by the driving in of the slide rails.
This invention addresses the problems detailed above, and as a trench shoring system that uses panels as shoring walls to prevent the possible collapse of natural ground walls of trenches when burying pipes underground, it not only prevents danger but also, compared to conventional technology, presents a remarkable improvement injob efficiency. Additionally, this invention offers shoring panels which contain mechanisms that prevent the two sliding panels from sliding beyond the specified sliding depth.